If male rats are tested with an estrus female they display mounts, intromissions and ejaculations in a certain temporal distribution. Drugs can be tested to determine their effects (beneficial or detrimental) on the latency and frequency of these male and female sexual behaviors.

Chronic treatment with paroxetine decreases sexual function as can be seen from the significant decrease in number of ejaculations (A) and the increase in latency to the first ejaculation (B).

Acute bupropion stimulates sexual function, with a significant increase in number of ejaculations (A) and a significant decrease in the latency to first ejaculation (B). However, chronic treatment is seen to have no effect on sexual function.